Photos and stuff from Antarctichron 2011 (for more info on Antarctichron, scroll down)

The 2011 Antarctichroners
(minus some folks and also including some adjunct folks) (left to right):
Sidney Hemming, Stuart Thomson, Willy Guenthner, Erin Adams, Kendra Murray, Ashley Contreras, Peter Reiners, Clare Tochilin, Elinor Utevsky (open your eyes, Nora), Elizabeth Pierce, Benedetta Andreucci, Alex Adler, and Adam Formica

Also muchas gracias for the helpful support from: Uttam Chowdhury, Mark Pecha, George Gehrels, Nicky Giesler, Bobby Bowman, John Krassikoff, Amanda Alfing, Christine Siddoway, and NSF Grant EAR-0910577!

All told Antarctichroners were able to analyze several hundred zircon and apatite U/Pb dates, about 150 apatite and 35 zircon (U-Th-Sm)/He dates, and combine these with hundreds of AFT dates and other geologic information to come up with 8 kick-ass geologic studies spanning the continent of Antarctica, grains from 3.2 Ga to 20 Ma, and stories ranging from glacial incision, plateau collapse, iceberg armadas, enigmatic Cenozoic magmatism, and rocks that stayed colder than 50 °C for 1.4 billion years. Watch for the Nature articles coming out in the next few months.

Adam and Benedetta plucking apatites from fission-track mounts with sadistic grins. These poor grains have already been abducted from cores offshore Antarctica, etched with acid, irradiated in a reactor, shot with an excimer laser, and are now about to be cooked with an IR laser, followed finally by a euthanasiac final dissolution in nitric acid.
Part of the Achron group hiking out of Aravaipa Canyon on the field trip. It was 113 °F this day in Tucson and probably about the same temperature in the canyon. These folks are tough.
Clare firing away at more unfortunate Late Miocene apatites from offshore Prydz Bay with the CO2 laser.

The view from our lunch stop in Aravaipa, including a sweet Proterozoic-Oligocene unconformity.

Ashley and Nora teach Alex how to lase empty Nb tubes with the Nd:YAG laser. Shut up! It's not funny! Ok, two of them had grains in them.

Benedetta explains the hunt for the elusive 30-Ma West Antarctic magmatic complex.

Nora explains the thermochronologic record of plateau collapse and glacial incision along the Byrd Glacier valley. Weird that the ages keep coming out like Durango....hmmm.

Ashley lasin' the hell out of some zircons from near the Weddell Sea. Who knew "the Laramide" happenned in East Antarctica too?

What could be less ironic for an Antarctic workshop than a fieldtrip in July in southern Arizona? See those white veins on the right side of the river there? Get ready to date the deformation associated with their formation.

Pluckin' apatite from epoxy AFT mounts...

Sid showing off some cool en echelon quartz-hematite veins in the Proterozoic basement of Aravaipa. I'll give you $5 if you guess how old those things are. Note Sid's cool Lamont Ar/Ar lab T-shirt. We should design something like that. Let's see...HElium Geochronology for Earth History And Geostuff...HEGEHAG...hmm.

Adam with some really cool data. If you could see those axes you'd see AFT ages of 250 Ma and AHe ages of 400 Ma. "Impossible," you say? Hah! Wait till you see the cover of Nature article about it. Or the AGU abstract at least.

More background about Antarctichron

Antarctichron 2011
Geochronology and Thermochronology Workshop at Arizona

Antarctichron is a two-week geo- and thermochronology workshop emphasizing methods and interpretations of U/Pb and (U-Th)/He (and some fission-track and other types of chronometry) as applied to geologic problems in Antarctica. It is aimed primarily at advanced undergraduate and early-career graduate students who are working on their senior theses or are in the early phases of their graduate research. The goals of the workshop are 1) to provide an opportunity for students to perform geochronologic and thermochronologic analyses on their own samples and 2) to provide some training and experience in the fundamentals of geochronology/thermochronology, diffusion, and analytical techniques, and 3) to provide an integrated perspective on geologic processes and phenonomena in Antarctica that can be addressed through radioisotopic dating.


Information on previous workshops (e.g., HeDWaY and HeDWaAZ).

Antarctichron 2011 Tentative Dates
17 June - 1 July
(arrival 16 June, departure 2 July)

Instructors: Peter Reiners, Stuart Thomson, & Sidney Hemming
with help from Uttam Chowdhury, Mark Pecha, and George Gehrels 




Student Name
Adam Formica
Columbia University
Measuring erosion rates during East Antarctic Glaciation at the Eocene-Oligocene transition using Ar/Ar on hornblende and biotite and triple-dating apatite and zircon
Benedetta Andreucci
University of Padova
Detrital thermchronology of the Southern Victoria Land, Antarctica
Ashley Contreras
Colorado College
Apatite (U-Th)/He Thermochronology and U-Pb detrital zircon analysis of migmatites from a Cretaceous gneiss dome in West Antarctica
Alex Adler
Columbia University
Thermochronology of  Amery Group sediments from Prydz Bay
Elinor Utevsky
Occidental College

Collapse of a Mesozoic West Antarctic Plateau: Evidence from Apatite (U-Th)/He Thermochronology

Erin Adams
University of South Carolina
Detrital thermochronology of Larsen Basin Antarctica
Clare Tochilin
University of Arizona
Triple-dating detrital zircon and apatite in Miocene cores, Prydz Bay, East Antarctica
Elizabeth Pierce
Columbia University
Comparison of U/Pb zircon and Ar/Ar hornblende and biotite detrital provenance evidence for thermochronology of subglacial terrains around Antarctica


Rationale and general description

The goal of Antarctichron 2011 is to introduce undergraduate and graduate students to geo- and thermochronology through some applications to the geology of Antarctica. Students will analyze and interpet their own samples and data, in the context of their own research projects. Through both hands-on analyses and interpretations, as well as informal lectures and discussions, students will learn fundamentals of radioisotopic dating, laboratory techniques, analytical instrumentation, basics of thermochronologic modeling, the geology of Antarctica, and each others' research projects. Each student's project during the workshop will focus on a small set of samples to be dated by (U-Th)/He, U/Pb, and in some cases, fission-track methods. Ideally, a student's accomplishments at this workshop should complement a larger research project supervised by the student's faculty advisor at his or her home institution.


Important points

[1] Unless other arrangements have been made, students must arrive with mineral separates already prepared and ready to pick under the microscope. We will not perform mineral separations here, so please insure that good clean mineral separates are completed and available well before the workshop starts. For students wishing to perform U/Pb analyses, it would be a good idea to have your grain mounts made, characterized by SEM if necessary, and ready to rock once you arrive. If this isn't possible, please make sure you've made arrangements with Pete beforehand.


[2] If you want to do (U-Th)/He dating be prepared for the possibility that your chosen samples/field area may not have usable material for (U-Th)/He dating. This is especially important for apatite He dating, as the method has stringent requirements of crystal morphology and purity. Think about a backup plan, and bring several sets of samples so that you have a better chance of obtaining some data that are useful and interesting.


[3] There is no requirement for direct faculty involvement in the workshop, beyond general supervision of student research and help with data interpretation at the student's home institution. If faculty would like to attend and participate in the workshop however, they are certainly more than welcome at any point, to learn about the technique and to facilitate future use of the lab by other students or themselves.


[4] Please bear in mind that actually accomplishing everything we want to do and obtaining real, good, usable data with geologic significance for everyone requires proper alignment of various cosmic bodies, good karma, properly functioning analytical equipment, lack of power outages, fully functioning and healthy instructors and lab managers, and you name it. We have done this before and know how to take appropriate steps to maximize the chances of all this. But be aware that sometimes feces happens. We will all work together to avoid and ameliorate fecal outcomes, but there's no guarantee.


Accomodations, food, other logistics

[1] Room and board will be covered by Antarctichron, through funds from NSF's Geochemistry and Petrology program as well as the Antarctic Earth Sciences program. Students will stay on campus in Kaibab-Huachuca Hall, in single rooms. These are very close (easy walking distance) to Gould-Simpson, where we will be working. These are pretty standard dorm rooms, and full linen service will be available. Yes, there is air conditioning. I hope.


[1.5] Students should plan on showing up at Kaibab-Huachuca Hall, see map here, sometime between 2 and 5 pm, on June 16th. Someone will be there to let you in and make sure you get settled. If you can't make this arrival/check-in time, please make sure you've arranged this with me (Pete). Then let's meet at 9 am on Friday 17 June in Gould-Simpson in room 517.


[2] Students will eat in cafeterias and other on-campus food venues that are within easy walking distance. You will have ID cards that allow you to spend a certain amount (should be more than enough for plenty of sustenance!) each day.


[3] Internet and email access is available through the UA Public Wifi. Computers will be available for student use in Gould-Simpson, but if you have a laptop, it might be a good idea to bring it.


[4] We will provide a chemical and laboratory safety training the first day of the workshop, to acquaint students with lab safety and hazards.


[5] There will be a one-day field trip on June 27th, to take a break from labwork and lectures, and to see some regional geology. Hopefully this will be iin Aravaipa Canyon. We will provide vehicles and transportation.


[6] Information about visiting UA, including links to maps and directions.


[7] If you intend to bring your own vehicle, contact Pete for information on parking.



Tentative schedule

The general daily routine will be a combination of laboratory work and one or two lectures and discussions, broken up by lunch.


In order to accomplish everything we need to do and make sure everyone gets at least some data to ponder, the beginning of the workshop will be pretty hectic. The first day will include some orientation, lab safety training, and an overview of Antarctic geology talk by Christine Siddoway. We will also start with sample preparation, and probably some U/Pb analyses right away that day.


A lot of you will spend time doing picking on the microscopes, followed by analyses on the He lines, followed by ICP-MS analyses for U-Th-Sm. Some of you will also do U/Pb dating in the Arizona Laserchron Center. This mostly involves sample picking under the microscopes for the first few days. Because we only have three picking microscopes, and also because no one can or wants to pick for more than a few hours at a time, students will take turns picking, and doing some library research in the first few days. As samples become ready, students will process them on the He line. This means running the laser to extract He, and operating the programs that spike, purify, and measure the gas.


Students will then perform wet chemistry involved with spiking, dissolution, and measurement of U, Th, and Sm on the high-resolution ICP-MS. After calculating ages from their measured data, and making corrections for alpha ejection, students will learn how to interpret He ages, in terms of forward and inverse thermal models, complexities that arise from topography, non-constant geothermal gradients, and other factors.


Finally, students will compile and synthesize their data and relate them to their larger project, and prepare a short presentation for the group on their results.


Tentative Schedule: Antarctichron 2011 (subject to change as plans evolve)
Sunday Monday Tuesday Wednesday Thursday Friday Saturday
June 12 June 13 June 14 June 15

June 16

arrive in the afternoon; check into K-H 2-5 pm

June 17

intro lectures; lab safety

Siddoway: Intro to Geology of Antarctica

Picking clinic

U/Pb dating

June 18

mineral picking;

Hemming: Antarctica, I.

U/Pb dating

June 19

mineral picking;

Hemming: Antarctica, II.

Reiners: He dating, I.

U/Pb dating

June 20

mineral picking;

He analyses

Reiners: He dating, II.

U/Pb dating

June 21

mineral picking;

He analyses

Gehrels: U/Pb dating


June 22

mineral picking;

He analyses

Thomson: FT dating


June 23

mineral picking;

He analyses;

Pierce: Wilkesland

all zircs in oven

June 24

He analyses;

spiking, dissolution

talk: TBA

zircs HF day 1

June 25

He analyses (aps only);

spiking, dissolution

talk: TBA

zircs HF day 2

June 26

He analyses (aps only);

spiking, dissolution

zircs HF day 3
zircs back in oven

June 27

Field trip to Aravaipa Canyon

zircs out of oven
dissolved in HNO3

all remaining aps spiked, dissolved

June 28

He analyses;

ICP-MS analyses;


June 29

ICP-MS analyses;

data interpretation

June 30

data interpretation;

prepare presentations

July 1

final presentations

July 2

leave UA/Tucson


Last updated 10 July 2011